DC-link control of a three-level NPC inverter fed by shaded photovoltaic system

This paper proposes a system composed of a three-level Neutral Point Connected inverter fed by photovoltaic panels. The system is able to operate adequately even under partial shading operation by controlling the DC-link neutral point injected current. System model, PWM strategy, maximum power point tracking, and control logic for balancing the DC-link capacitors voltages are presented. Experimental results corroborate the theoretical studies.